Semi-insulating gallium arsenide (SI-GaAs) has gained great interest in recent years due to its wide application in optoelectronic devices and high-speed integrated circuits. An important feature of SI-GaAs is the high density of deep-level defect states, which control the electrical properties of the substrate by compensating the shallow defects. Over the years, deep-level transient spectroscopy (DLTS) and its variations have been the most effective tools employed for the characterization of deep-level defects. However, most of these techniques require a contact probe and tend to be quite restrictive in their applications’ scope. In this thesis deep-level photo-thermal spectroscopy (DLPTS), an all-optical rate-window-based technique, is presented as a novel noncontact technique for the characterization of deep-level defects in SI-GaAs. The signal-generation mechanism for DLPTS is the super-bandgap excitation of carriers, and the sub-bandgap detection of the defect’s thermal-emission process. Combined with the rate-window detection utilizing lock-in amplifiers, DLPTS measurements are performed in three different modalities: temperature-scan, pulse-rate scan, and time-scan. This work demonstrates that each mode provides unique information about the defect configuration, and, in combination, the modes offer a powerful tool for the study of defect properties and optoelectronic processes in SI-GaAs. A hierarchical carrier-emission theory is proposed to explain the thermal broadening (nonexponentiality) in photo-thermal spectra. The model is studied comparatively with the Gaussian distribution of activation energies, and their similarities demonstrate an ergodic equivalence of random energy distribution and the constrained hierarchical emission process. In addition, a rate-window gated photo-carrier radiometry (PCR) technique is developed. The original diffusion-based PCR theory is modified to reflect the signal domination by trap emission and capture rates in the absence of diffusion. Defect luminescence is collected and analyzed using photo-thermal temperature spectra and resonant detection combined with frequency scans. The study results in the identification of five radiative defect states and the defect-photoluminescence quantum efficiency.

Els Processos Avançats d'Oxidació (PAOs) són tècniques de degradació química basades en la producció in situ del potent reactiu radical hidroxil. L'acoblament entre PAOs i sistemes biològics pel tractament d'aigua contaminada amb compostos biorecalcitrants és una alternativa útil als mètodes de gestió convencionals. El principal benefici d'aquests tractaments acoblats és la minimització del pretractament químic fins a generar intermedis més biodegradables. Subseqüentment, un tractament convencional d'aigües residuals, basat en la activitat de microorganismes, es pot utilitzar per eliminar completament la matèria orgànica del medi.Aquest tesi desenvolupa una estratègia d'acoblament entre sistemes químics i biològics per tractar herbicides específics com exemple de contaminants tòxics i no biodegradables produïts per l'home. / Advanced Oxidation Processes (AOPs) are chemical degradation techniques based on the in situ production of the powerful reactive hydroxyl radical. The coupling between AOPs and biological systems for the treatment of water polluted with biorecalcitrant compounds is a useful alternative to conventional management methods. The main benefit of these coupled treatments is the minimization of the chemical pretreatment to generate more biodegradable by-products. Subsequently, a conventional wastewater treatment, based on the activity of microorganisms, can be used to completely remove organic matter from solution. This thesis deals with the development of a chemical and biological coupling strategy to treat some specific herbicides as examples of toxic and non biodegradable anthropogenic pollutants.

Single-walled carbon nanotubes (SWCNTs) are promising for use in solar cells and photodetectors because of their strong optical absorption in most of the solar spectrum. There have been many reports about the photovoltaic effect in nanoelectronic devices based on individual SWCNTs, but they have been limited by complicated fabrication and miniscule absorption. There has been a growing trend for merging SWCNTs into micro-and macroscopic devices to provide more practical applications. Here we report the photoresponse of macroscopic SWCNT films with a p-n junction at room temperature. Photovoltage (PV) and photocurrent (PC) due to the photothermoelectric (PTE) effect were observed at the junction, and they were larger by one order of magnitude as compared with their values at the metal-SWCNT interfaces. Various factors affecting PV amplitude and response time have been studied, including junction length, substrate, and doping level. The maximal responsivity we observed was 1V/W with samples on Teflon tape, while a fast response time 80 S was observed with samples on AlN substrates. Hence an optimal combination of photoresponse time and amplitude can be found by proper choice of substrate. It was found that PV increased nonlinearly with increase in n-doping concentration, indicating the existence of an optimal doping level. This result also suggests the possibility to further improve photoresponse by changing p-doping level. Finally, we checked the photoresponse in wide wavelength range (360-900 nm), and PV was observed throughout, indicating that the device could potentially be used as a broadband photodetector.

This work demonstrates the pretilt angle controllable photo-alignment effect in nanoparticles and azo-dye doped liquid crystal film. Followed by increasing the absorbed azo-dye, the vertical alignment induced by nanoparticles of polyhedral oligomeric silsesquioxanes (POSS) can be changed from high pretilt to low pretilt angle. Competition between the homogeneously aligned azo-dye and POSS-induced spontaneous vertical alignment domain generated the variable pretilt angle. The pretilt angle is a function of the pumping intensity and can be controlled continuously within the range of 0¢X~90¢X. With the sufficient absorption of photo excited azo-dye, The POSS induced vertical alignment can be switch to homogeneous alignment. The pretilt angle and surface energy are also examined to confirm the alignment effect. Both nanoparticles and azo-dye induced vertical and homogeneous alignment are non contact methods, and suitable for low temperature plastic process.

In this thesis, photocrosslinked ferrocene-based methacrylate polymers for thin-film cathodes in lithium batteries have been synthesized. Patterned thin-film electrodes of the ferrocene-based methacrylate polymers are fabricated by photocrosslinking. The structure and composition of the photocrosslinkable polymers are characterized by infrared spectra, nuclear magnetic resonances, and gel permeation chromatography. The result of quartz crystal microbalance shows that the crosslinked polymers prevent the polymers from dissolving into organic electrolytes. The cyclic voltammogram shows the photocrosslinked ferrocene-based methacrylate polymers have a redox couple. The energy capacity of the polymer for lithium batteries is about 40-50 mAh g-1 at a discharge rate of 10 C. The results show that the photocrosslinked ferrocene-based methacrylate polymers also improve the batteries.

We studied terahertz radiation from InN in our paper. We set up " Terahertz Time-Domain Spectroscopy system" and investigate Terahertz emission from InN. We take our sample(InN) in the rotation stage and we rotate different angle to detect the THz intensity data and wave shape and also the mechanisms of THz wave emitted. We research the influence from different background carrier density, band gap, mobility and structure(Zb-InN, W-InN) of InN to produce Terahertz radiation. Finally, we dicuss the THz amplitude and shape influenced from the internal surface field effect, Photo Dember effect, stacking fault, c-plane and m-plane from InN.

The objectives of this study are to know the behavioural response of the hagfish, Paramyxine cheni to light and to find out if various parts of hagfish¡¦s body differ in sensitivity to light. Photosensitivity was measured in terms of time lapsed between light on and initiation of behavioural sequence (i.e., the reactive time). Behavioral response was measured by the persistent time from the beginning and ending of the behavioural sequence. Five types of light were used as the stimuli to the whole animal: green light, blue light, yellow light, red light, and white light. The lineup of sensitivity for various wavelengths in increasing reactive times( ranging from 13 seconds to 180 seconds) is: green light, blue light, white light, yellow light, red light. Red light significantly differed from the other four types of light in the reactive time; the hagfish was significantly less sensitive to this red light. Four regions of the body were tested with white light: head, gill aperture, tail and mid-portion between the first gill aperture to cloaca. In addition, two parts of the body were simultaneous tested with stimulate: head and tail (HT). The lineup of sensitivity of various regions of body for increasing reactive times (ranging from 9 seconds to 1200 seconds) is: tail, head, mid-portion between the first gill aperture to cloaca, and gill aperture. Tail was significantly more sensitive than the other three parts of the body. However, sensitivity for HT was significantly higher than the tail. Hagfish¡¦s spontaneous movement (i.e., under dark condition)included a number of behavioural sequences differed in the arrangement of behavior patterns (i.e., rolling, swimming, wiggling, springing, and pause). ¡¥Rolling¡¦ was the most preferred initial pattern in a spontaneous movement sequence. In contrast, illumination on tail evoked a complex motor response. Thus, such response was considered not a simple reflex, but a select of choice. ¡¥Swimming¡¦, on the other hand, is the most preferred initial pattern in the sequence triggered by photo stimulation on the tail. According to fluoresence histochemistry study the rhodopsin-like protein is present in the large oval-shaped cells distributed in the epidermis of hagfish. the number and the size of photo-sensitive cells on the tail and gill aperture and the fluorescence intensity on the tail were significantly higher than that on the gill aperture region.

ASTRACT Using an aqueous solution of ammonia hydroxide aqua, hydrosilicofluoric acid and boric acid, an oxynitride film can be deposited. The deposition rate and refractive index increase with the mole concentration of ammonia hydroxide aqua. However, the refractive index decreases as the mole concentration of ammonia hydroxide aqua becomes too high. The leakage current density as a function of mole concentration of ammonia hydroxide aqua was studied. The best experimental condition is found that incorporating ammonia hydroxide aqua of 0.8M will get good results. The SIMS depth profiles shows nitrogen and hydrogen concentration accumulate at SiON/Si interface. A deposition model is proposed and LPD-SiON can be suggested that it is a combination of N-less LPD-SiON film and N-rich accumulated layer at the interface. The best characteristics of LPD-SiON film are in the range of 110Å-thick to 210Å-thick. When the thickness scales down to 110Å, all the properties become poor. Photo-LPD-SiON process is proposed as a reference of Photo-LPD-SiO2. By mercury lamp illumination, the performances of J-E relationship and C-V characteristic become better. Nitrogen atomic concentration can increase by photo-enhancement checked by analysis of SIMS depth profile and FTIR spectrum. A novel technique of LPD process with applying a bias during the growth is proposed and it is called Bias-LPD-SiON. A model of Bias-LPD-SiON deposition mechanism is also proposed. On the negative bias substrate, high nitrogen atomic concentration can be attained. The J-E characteristic at positive bias of 0.1V and negative bias in a range of 0.1V to 1V are better than traditional LPD-SiON film. Then, the deposition rate of positive bias and negative bias LPD-SiON films at 0.1V can reach 32Å/min and 26Å/min, respectively. Therefore, high quality and high deposition rate can be prepared by Bias-LPD-SiON.

Habitat associations of sea otters during resting and feeding were investigated in Simpson Bay, Prince William Sound, Alaska during the summer months of 2001-2003. Sea otter locations collected during boat surveys were overlaid on bathymetry and sediment maps and water depth, sediment type, distance from shore, and position in the bay (peripheral vs. central) was determined for each. Logistic regression analysis was used to determine whether sea otter habitat use was non-random according to any of these habitat variables. Water depth was the most significant habitat association for feeding behavior, with the majority of feeding dives occurring in shallow water less than 20m deep. Position in the bay was the most significant habitat association for resting behavior, with more otters resting in the center of the bay. In addition, digital images taken of the sea otters during the boat surveys of 2002 and 2003 were used to examine the potential of using nose scars to photo-identify individual sea otters. Both male and female sea otters bore nose scars. Forty-five percent of all individuals encountered were considered identifiable from nose scars and a total of 114 individuals were identified. This compares favorably with the results of photo-identification studies of other marine mammals, suggesting that photo-identification may be a useful tool for the individual identification of sea otters as well.

Ubiquitous computing describes the aspirations of including information systems into the fabric of our daily lives. The emphasis of the user should be on what task needs to be achieved rather than how the system will do it. The interface of applications that are integrated into the home fabric needs to be delicate in the sense that it should give the feeling of being a part of the home rather than a piece of technology. The human computer interaction/interface needs to be cohesive with the environment people live in so as to maximise the interaction possibilities. Photographs are a very affective and efficient way of connecting people to each other. We should not forget the social role photographs have to play. The most important aspect of the picture is the story that it is trying to convey, the people in it, or the place it was taken. Emotions are a very private part of our personal life and how one displays it reflects one’s lifestyle. In recent years increasing efforts have been put into preserving emotions in photos particularly with the advent of digital cameras. Now photographs have become an important part of our lives and have significant social role as they provide an affective communication link between friends and families. This research will be looking at how people relate themselves to pictures and if we could capture their emotions and expressions to store them in a way that is representative of their feelings towards the picture. As emotions can be associated with pictures of family, friends, places, holidays, social gatherings or travel to mention some of the aspects, we will also be analysing as to how emotions change over a period of time and if it could be represented accordingly in association with digital photos. This will allow us to look into the factors, which can make digital photo sharing a more fun and enjoyable experience. This research will involve user based evaluations and a scenario based approach for modelling the photo sharing interface. The creation of photo sharing system, based on this approach, is then investigated using the method of prototyping. The research shows methods, architectures, and tools used to make the development process more efficient and help assess the viability of the system under conditions that simulate to everyday use of the photo sharing software. To generalise and communicate results, the project will seek to simulate the home environment in a laboratory setting, using prototypes based on current high-end computing devices. The .Net technologies used for rapid prototyping is introduced. The aim of this research is to provide a demonstration environment of a photo sharing software for the smart home, which will allow for Reception/Viewing/distribution of photos within the home environment. The data could incorporate Audio/Video/Text/Photos, and user input etc. The research will also help us understand various aspects of how people interact with Digital Photos, what they would like to do, how can storing photos be made simpler, annotation of pictures, how can sharing photo’s made simpler, and how we can design an application which would allow users to attach emotions to pictures. The photo sharing system will provide an effective means to receive and distribute emotional information based on personal and temporal relationships associated with photos. The research also analyses the role of human computer interaction when developing ubiquitous technologies for the smart homes where information is embedded in the environment people live in. The research will present an overview of how photo sharing systems can be developed and evaluated using prototypes and user evaluations.